Field of the Invention
The present disclosure generally relates to a microorganism expressing FrsA protein or mutant form thereof and methods of producing ethanol using the same.
Description of the Related Art
Efforts to reduce heavy reliance on foreign oil as well as environmental damages have led to efforts to find alternative energy sources. One of them is to produce bioethanol from biomass.
However, the progression of bioethanol production has been hampered due to its low efficiency and high cost of production. Thus there are needs to improve the process to increase the economics and to lower investment risk. The efforts are generally focused on the development of a conversion process to change the biomass into materials so that it can be utilized by microorganisms as a glucose source; and on the development and improvement of enzymes involved in the glucose metabolism in cells.
In the process for producing bioethanol using microorganisms such as Saccharomyces cerevisiae, Zymomonas mobilis or Escherichia coli and the like, sugars such as hexose or pentose are fermented to produce bioethanol.
Theses microorganisms are often genetically modified to express exogenous enzymes to improve the efficiency of ethanol production. Such exogenous enzymes are represented by pyruvate decarboxylase (PDC) and alcohol dehydrogenase (ADH). When E. coli are used as a host cell, PDC and ADH derived from Zymomonas mobilis have been utilized to convert pyruvates to ethanol.
These enzymes have capabilities to increase the efficiency of the ethanol production thus reducing the amount of biomass used in the process. Therefore modification of the enzymes to improve their activity plays a major role in reducing the total cost of the process.
US Patent Publication No. 2009/0155871 discloses a construct having a photo responsive promoter and genes encoding PDC and ADH from Zymomonas mobilis and methods to produce ethanol using cyanobacteria transformed with the same.
KR Patent Publication No. 2011-0007981 discloses a novel ADH and methods for producing ethanol using a microorganism transformed with the same.
KR Patent Publication No. 2012-0082141 discloses a method to produce ethanol using the strain which has been modified to reduce its glycerol production and transformed with ADH and PDC from Saccharomyces cerevisiae. 
However, there are no reports using FrsA from Vibrio vulnificus as PDC to improve the ethanol production in cells and there are needs to develop new strains which are able to produce ethanol.